Exam 2 Lecture - Development of the Digestive System Flashcards
What modifications do horses have to their GI tract?
- illeum opens directly into the cecum
- cecum is about a meter in length
- ascending colon is very large
What modifications do ruminants have to their GI tract?
- four chambered stomach
- cecum is bigger than the carnivore cecum
- ascending colon is very large
What are the foregut derivatives?
- esophagus
- stomach
- descending duodenum
- liver
- pancreas
What is the foregut’s blood supply?
celiac artery
What are the midgut derivatives?
- ascending duodenum
- jejunum
- ileum
- cecum
- ascending and transverse colon
What is the midgut’s blood supply?
cranial mesenteric artery
What is the hindgut derivative?
descending colon
What is the hindgut supplied by?
the caudal mesenteric artery
How is the simple stomach rotated into the position that it is in in its adult form?
- Will have a 90 degree rotation around the longitudinal axis brings the dorsal part (greater curvature) of the stomach to the left
- Second rotation brings the caudal part of the stomach cranially and to the right
What are the two mesenteries that support the embryologic gut tube?
dorsal and ventral mesentery
How does the dorsal mesentery allow for the turns of the stomach?
it undergoes replication and growth which in turn creates deep leaf and superficial leaf
What does the dorsal mesentery become?
the greater omentum
What does the ventral mesentery become?
the lesser omentum
What are the parts of the ruminant stomach?
rumen, reticulum, omasum, and abomasum
What does elongation of the dorsal mesentery and cranial mesenteric artery do in relation to the mesentery?
allows the midgut to form a loop shape (cranial and caudal limb)
What causes a physiological herniation?
as the liver grows, it pushes the loop out of the body
How does intestinal rotation occur?
- Cranial limb undergoes explosive growth causing it to pass to the right side of the cranial mesenteric artery – now in a caudal location
- This movement displaces the caudal limb – cranially
- Explosive growth continues and it displaces cranially again pushing the caudal limb to the right
- Twisting creates the root of the mesentery (270 degree spin)
What is the cloaca closed by?
cloacal membrane
What is the function of the urorectal septum?
divides the cloacal membrane into anal membrane and urogenital membrane
intestinal stenosis
airway of the intestines
intestinal atresia
section of the intestines that disappears
happens during turning
atresia ani
anal membrane does not break down
urorectal fistula
abnormal communication between the rectum and the urinary system
failed to completely divide
